The state-of-heath (SOH) of a rechargeable battery is a metric relating to the battery's power and energy delivery capability, as well as the efficiency with which the battery is charged from dynamic and static charging sources, all characteristics which tend to decay over the battery's useful life. Accordingly, in the context of an electrically powered vehicle, accurate determination of the battery SOH tends to be critical in accurately predicting or determining driving range, acceleration, charging time, ability to recover energy from regenerative breaking, and, ultimately, end of useful life.
Despite the critical importance of obtaining accurate SOH metrics, conventional techniques rely on individual determinations of DC resistance (DCR) taken under varying conditions, which has the disadvantage of resulting in varying determinations of DCR for a battery with a particular SOH and consequently less accurate determinations of SOH.